The excision of tumors that cover a large area in the gastrointestinal tract and that are restricted to the mucosa should take place in one session, if possible, and should be complete, if possible. This is usually done using a loop or cap technique, by means of which essentially circular resectates having different sizes that are strictly a function of the loop or cap diameter are obtained. Large-area tumors having a diameter greater than 8 cm can be ablated only in partial steps.
In order to perform such a total operation, publication DE 10 2005 038 694 A1 has suggested an endoscopic instrument that combines a device for water jet surgery with a device for RF surgery to be handled as a unit. As a result of this, a multifunctional instrument is provided that is intended to combine the advantages of water jet surgery with those of RF surgery. The instrument allows a metered injection of an NaCl solution under the mucosa in order to lift the mucosa off the muscularis. Furthermore, this instrument also allows a separation with the use of the fluid jet. For separating the submucosa, the device is used for RF surgery. Thus, one and the same instrument can be used for performing two successive operative steps—without any instrument change. The design of this instrument provides for two channels extending from the proximal end to the distal end of the instrument, i.e., a first channel for the cutting fluid and a second channel accommodating the RF surgical instrument so that it can be moved. Both channels are jacketed by a shared protective sheath and thus form a unit. The distal end of the first channel has a nozzle in order to be able to eject the fluid jet at sufficient speed or with sufficient energy in order to be able to achieve said cutting effect.
During surgery using this instrument, it is necessary to work with two different instruments projecting on the distal end of the instrument. Though these instruments existing in a combined instrument, the full attention of the surgeon is still required. Furthermore, this instrument may be expensive to manufacture because specifically dedicated “instruments” are necessary for the nozzle of the water jet surgical device, on the one hand, and for the RF surgical device, on the other hand.
Publication EP 0 280 972 A1 discloses a surgical instrument for open surgery, namely, a handle for surgical use, the handle including a combination of a fluid jet cutting instrument and an RF coagulation instrument, thus allowing the immediate coagulation—i.e., closure, of vessels that are bleeding after having being cut with the fluid jet—by means of an instrument using RF. To accomplish this, the handle comprises, on its distal end, a coagulation electrode that, at the same, time accommodates an outlet nozzle for the cutting fluid. With this instrument, it is not possible to operate endoscopically because an unwanted contact of tissue within the body cavity cannot be avoided. Additionally, a cutting with RF current is not possible using this instrument. Furthermore, with this instrument, it is not possible to mark planned cutting edges prior to the actual dissection, which thus requires planning and recording, on the one hand, and cutting, on the other hand, to occur in two phases, in order to ensure greater safety.
Considering the aforementioned prior art, it is the object of the disclosed embodiments to provide an endoscopic surgical instrument that is simple in design and is easy to handle, so that, in particular, a mucosa elevation and resection can be performed in a single procedural step. Furthermore, it is the object of the invention to provide an method for the manufacture of such an instrument.